The Nottingham Canal was dug in the 1790s and closed for ever in 1937. For the last 70 years it has gently decayed, becoming filled with rubbish, obliterated by mining and industrial development. But here and there along its 14 mile length it survives still, the haunt of herons and swans. We walked a little of its towpath on a peaceful winter afternoon as the sun descended behind the ridge on which stands Ilkeston, Derbyshire.